package com.tingyuge.base.structrue.trie;


import java.util.TreeMap;

/**
 * @Created by xiaodao
 */
public class Trie {

    private class Node {
        public boolean isWord;

        public TreeMap<Character, Node> next;

        public Node(boolean isWord) {
            this.isWord = isWord;
            next = new TreeMap<>();
        }

        public Node() {
            this(false);
        }
    }


    public Node root;
    private int size;

    public Trie() {
        root = new Node();
        size = 0;
    }


    public int getSize() {
        return size;
    }

    /**
     * 添加一个新的单词word
     *
     * @param word
     */
    public void add(String word) {
        Node cur = root;
        for (int i = 0; i < word.length(); i++) {

            char c = word.charAt(i);
            if (cur.next.get(c) == null) {
                cur.next.put(c, new Node());
            }
            cur = cur.next.get(c);
        }
        if(!cur.isWord){
            cur.isWord = true;
            size++;
        }
    }
    //查询单词
    public boolean contains(String word){
        Node cur = root;
        for (int i = 0; i < word.length(); i++) {

            char c = word.charAt(i);
            if (cur.next.get(c) == null) {
                return false;
            }
            cur = cur.next.get(c);
        }
       return cur.isWord;
    }

    //查询是否在trie中有单词prefix前缀
    public boolean isPrefix(String prefix){
        Node cur = root;
        for (int i = 0; i < prefix.length(); i++) {

            char c = prefix.charAt(i);
            if (cur.next.get(c) == null) {
                return false;
            }
            cur = cur.next.get(c);
        }
        return true;
    }

}
